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Context: Health care providers must be prepared to manage all potential spine injuries as if they are unstable. Therefore, most sport teams devote resources to training for sideline cervical spine (C-spine) emergencies. Objective: To determine (1) how accurately rescuers and simulated patients can assess motion during C-spine stabilization practice and (2) whether providing performance feedback to rescuers influences their choice of stabilization technique. Design: Crossover study. Setting: Training studio. Patients or Other Participants: Athletic trainers, athletic therapists, and physiotherapists experienced at managing suspected C-spine injuries. Intervention(s): Twelve lead rescuers (at the patient's head) performed both the head-squeeze and trap-squeeze C-spine stabilization maneuvers during 4 test scenarios: lift-and-slide and log-roll placement on a spine board and confused patient trying to sit up or rotate the head. Main Outcome Measure(s): Interrater reliability between rescuer and simulated patient quality scores for subjective evaluation of C-spine stabilization during trials (0 = best, 10 = worst), correlation between rescuers' quality scores and objective measures of motion with inertial measurement units, and frequency of change in preference for the head-squeeze versus trap-squeeze maneuver. Results: Although the weighted κ value for interrater reliability was acceptable (0.71–0.74), scores varied by 2 points or more between rescuers and simulated patients for approximately 10% to 15% of trials. Rescuers' scores correlated with objective measures, but variability was large: 38% of trials scored as 0 or 1 by the rescuer involved more than 10° of motion in at least 1 direction. Feedback did not affect the preference for the lift-and-slide placement. For the log-roll placement, 6 of 8 participants who preferred the head squeeze at baseline preferred the trap squeeze after feedback. For the confused patient, 5 of 5 participants initially preferred the head squeeze but preferred the trap squeeze after feedback. Conclusions: Rescuers and simulated patients could not adequately assess performance during C-spine stabilization maneuvers without objective measures. Providing immediate feedback in this context is a promising tool for changing behavior preferences and improving training.

Small bowel obstruction (SBO) is a particularly vexing problem in the postoperative period. The goal of this study was to compare the results of operative versus nonoperative treatment. A secondary goal was to explore risk factors for necessitating reoperation in the immediate postoperative period. We conducted a historical cohort retrospective chart review at a university-affiliated hospital. The medical records of patients treated between 1985 and 2000 at the Sir Mortimer B. Davis Jewish General Hospital (Montreal, Quebec, Canada) who developed SBO after undergoing a laparotomy during that admission were reviewed. Postoperative SBO was defined as cessation of flatus or bowel movements after their resumption following operation. To compare operative versus nonoperative management of early postoperative mechanical SBO we used the following outcome measures: Reoperation rate, time to return of function, length of stay, and mortality. Of 52 patients who developed SBO in the immediate postoperative period 37 were male, 25 had colorectal surgery, and nine had a gastrectomy as the initial operation on admission; five had inflammatory bowel disease, six had a previous SBO, 22 had virgin abdomens before the current operation, and 11 had adhesions noted at the initial operation. The median time to the development of obstructive symptoms was 8 days (range 1–33). The reoperation rate was 42 per cent overall (67% in women and 32% in men, P = 0.02). For operatively treated patients the median time between onset of symptoms and surgery was 5 days [range 1–23, interquartile range (IQR) = 5]. The median time to the return of bowel function was greater in the operatively treated patients compared with nonoperatively treated patients [11.5 days (range 4–37, IQR = 11) vs 6 days (range 1–28, IQR = 7), P < 0.0001] as was median length of stay from onset of obstruction [23 days (range 6–60, IQR = 14) vs 12 days (range 2–45, IQR = 16), P < 0.009]. Operatively treated patients also stayed longer after their obstruction was relieved although not significantly longer [8 days (range 1–35, IQR = 11) vs 4.5 days (range 0–40, IQR = 10), P = 0.15]. There were 11 complications in nine of 22 patients who underwent operative treatment of their SBO. Immediate postoperative SBO can be treated nonoperatively in stable patients resulting in significantly quicker return of bowel function and shorter lengths of hospital stay. Definitive risk factors for immediate SBO could not be identified.

OBJECTIVE: To examine if different definitions of "recurrent injury" affect the distribution of subsequent injury types and their consequences. DESIGN: Secondary analysis of prospective injury data. SETTING: Circus shows. PARTICIPANTS: Circus artists (n = 1281). MAIN OUTCOME MEASURES: A subsequent injury after an index injury was categorized as (1) new injury: different location; (2) local injury: same location, different type; and (3) recurrent injury: same location/type. Subsequent injuries were stratified according to when they occurred after the index injury: early (≤90 performances), late (91-540 performances) and delayed (>540 performances). "Healed injury" was either date of return to full participation (RTP) or last treatment. RESULTS: Eight hundred twenty-one artists (64%) incurred 2 medical attention injuries, and 296 artists (23%) incurred 2 time loss injuries. In both medical attention and time loss injuries, recurrent (range, 7.5%-8.3%) and local injuries (range, 4%-7%) occurred less frequently than subsequent new injuries (range, 81%-87%). Time loss injuries recurred later than medical attention injuries. The pattern of early, late, and delayed injuries was similar for new, local, and recurrent injuries. A greater number of "early" injuries are seen with the treatment definition compared with RTP. Subsequent injuries had similar number of treatments and missed performances (consequences) as index injuries. CONCLUSIONS: In our data, there were a greater number of local and recurrent time loss injuries compared with medical attention injuries, but the injury definition did not affect the relative number of early, late, or delayed injuries. Recurrent injuries are an important component of injury prevention, and clear definitions when presenting recurrent injury data are necessary. Language: en

Decreasing latitude and increasing frequency of population lactase nonpersistence have been reported to diminish risks for several diseases, but the reason for overlap has not been explained. We evaluate, relationships between calculated national annual ultraviolet light B (UVB) exposure, latitude, and national lactose digestion frequencies. Annual UVB exposure and latitude were based on weighted averages from several cities in different countries. Lactase distribution status was based on published data that have been used previously to derive relations with diseases. We compare univariate regression analyses (r(2)(adj), slope) of percentage of lactase nonpersistence with UVB or latitude. We determine, differences between European and non-European sources by multiregression analysis of independent variables. Correlation between UVB and latitude is high (r(2) = 0.89), and between percentage of lactase nonpersistence and either latitude or UVB the correlation is moderately strong with r(2) = 0.51 and 0.46, respectively, with P ≤ 0.01 for both. A more detailed analysis shows that correlations between percentage of lactase nonpersistence and UVB are only significant in Europe, r(2) = 0.59, P < 0.001, whereas outside Europe: r(2) = 0.06, P = 0.16. These relationships raise hypothetical explanations to account for the observed overlap in similar risk modification by the 2 variables.

Methods to calculate bias-adjusted estimates for meta-analyses are becoming more popular. The objective of this paper is to use the structural approach to bias and causal diagrams to show that (i) the current use of the bias-adjusted estimating tools may sometimes introduce bias rather than reduce it and (ii) the Cochrane collaboration risk of bias tool, which was designed for randomized studies, is also applicable to non-randomized studies with only minimal changes. Causal diagrams are used to illustrate each of the items in the current risk of bias tool and how they apply to both randomized and non-randomized studies. With the exception of confounding by indication, the structure of all potential biases present in non-randomized studies may also be present in randomized studies. In addition, causal diagrams demonstrate important limitations to the methods currently being developed to provide bias-adjusted estimates of individual studies in meta-analyses. Finally, causal diagrams can be helpful in deciding when it is appropriate to combine studies in a meta-analysis of non-randomized studies even though the studies may use different adjustment sets. Copyright © 2012 John Wiley & Sons, Ltd.

Objective To analyse published articles that used interventions aimed at investigating biomechanical/physiological outcomes (ie, intermediate risk factors) for sport injury prevention in order to characterise the state of the field and identify important areas not covered in the literature. Data sources PubMed, Cinahl, Web of Science and Embase were searched using a broad search strategy. Main results Only 144 of 2525 articles retrieved by the search strategy met the inclusion criteria. Crossover study designs increased by 175% in the late 1980s until 2005 but have declined 32% since then. Randomised controlled trial (RCT) study designs increased by 650% since the early 1980s. Protective equipment studies (61.8% of all studies) declined by 35% since 2000, and training studies (35.4% of all studies) increased by 213%. Equipment research studied stability devices (83.1%) and attenuating devices (13.5%) whereas training research studied balance and coordination (54.9%), strength and power (43.1%) and stretching (15.7%). Almost all (92.1%) studies investigated the lower extremity and 78.1% were of the joint (non-bone)-ligament type. Finally, 57.5% of the reports studied contact sports, 24.2% collision and 25.8% non-contact sports. Conclusion The decrease in crossover study design and increase in RCTs over time suggest a shift in study design for injury prevention articles. Another notable finding was the change in research focus from equipment interventions, which have been decreasing since 2000 (35% decline), to training interventions, which have been increasing (213% increase). Finally, there is very little research on overuse or upper extremity injuries.

To compare head motions that occur when trained professionals perform the head squeeze (HS) and trap squeeze (TS) C-spine stabilization techniques.Cross-over design.Twelve experienced lead rescuers.Peak head motion with respect to initial conditions using inertial measurement units attached to the forehead and trunk of the simulated patient. We compared both HS and TS during lift-and-slide (LS) and log-roll (LR) placement on spinal board, and agitated patient trying to sit up (AGIT-Sit) or rotate his head (AGIT-Rot). The a priori minimal important difference (MID) was 5 degrees for flexion or extension and 3 degrees for rotation or lateral flexion.The LS technique was statistically superior to the LR technique. The only differences to exceed the MID were extension and rotation during LR (HSTS). In the AGIT-Sit test scenario, differences in motion exceeded MID (HSTS) for flexion, rotation, and lateral flexion. In the AGIT-Rot scenario, differences in motion exceeded MID for rotation only (HSTS). There was similar intertrial variability of motion for HS and TS during LS and LR but significantly more variability with HS compared with TS in the agitated patient.The LS is preferable to the LR when possible for minimizing unwanted C-spine motion. There is little overall difference between HS and TS in a cooperative patient. When a patient is confused, the HS is much worse than the TS at minimizing C-spine motion.

Background Exercise training may have the potential to improve post-thrombotic syndrome, a frequent, chronic complication of deep venous thrombosis. We conducted a randomized controlled two-centre pilot trial to assess the feasibility of a multicentre-based evaluation of a six-month exercise training program to treat post-thrombotic syndrome and to obtain preliminary data on the effectiveness of such a program. Methods Patients were randomized to receive exercise training (a six-month trainer-supervised program) or control treatment (an education session with monthly phone follow-ups). Levels of eligibility, consent, adherence and retention were used as indicators of study feasibility. Primary outcomes were change from baseline to six months in venous disease-specific quality of life (as measured using the Venous Insufficiency Epidemiological and Economic Study Quality of Life [VEINES-QOL] questionnaire) and severity of post-thrombotic syndrome (as measured by scores on the Villalta scale) in the exercise training group versus the control group, assessed by t tests. Secondary outcomes were change in generic quality of life (as measured using the Short-Form Health Survey-36 [SF-36] questionnaire), category of severity of post-thrombotic syndrome, leg strength, leg flexibility and time on treadmill. Results Of 95 patients with post-thrombotic syndrome, 69 were eligible, 43 consented and were randomized, and 39 completed the study. Exercise training was associated with improvement in VEINES-QOL scores (exercise training mean change 6.0, standard deviation [SD] 5.1 v. control mean change 1.4, SD 7.2; difference 4.6, 95% CI 0.54 to 8.7; p = 0.027) and improvement in scores on the Villalta scale (exercise training mean change −3.6, SD 3.7 v. control mean change −1.6, SD 4.3; difference −2.0, 95% CI −4.6 to 0.6; p = 0.14). Most secondary outcomes also showed greater improvement in the exercise training group. Interpretation Exercise training may improve post-thrombotic syndrome. It would be feasible to definitively evaluate exercise training as a treatment for post-thrombotic syndrome in a large multicentre trial.

OBJECTIVE:: Return-to-play (RTP) decisions are a central component of the Team Physician's clinical work, yet there is little more than anecdotal reference to these in the literature. We recently published a 3-step model for return-to-play medical decision making and, in the current paper, undertook a systematic review of the literature to determine the level of evidence in support of this model. DATA SOURCES:: PubMed, Web of Science, and CINAHL electronic databases. Any article specifically related to concussion, head injuries, neck injuries, illness, medical conditions (including cardiovascular and renal), and preparticipation in sport or that reported RTP as a clinical outcome was excluded. Any article that contained a discussion on one of the components of the 3-step decision-based RTP model was included. RESULTS:: We reviewed 148 articles that met the criteria for inclusion and found 98 review articles, 39 original articles, 6 case reports, and 5 editorials. Of these, 141 articles mentioned Step 1 of the medical decision-making process for RTP (Medical Factors), 26 mentioned Step 2 (Sport Risk Modifiers), and 20 mentioned Step 3 (Decision Modifiers). Of the 148 articles in total, only 13 focused on RTP as the main subject and the remaining 135 mentioned RTP anecdotally. Of these 13 articles, 5 were reviews, 4 were editorials, and 4 were original research. CONCLUSIONS:: Although 148 articles we retrieved mention RTP in relation to a specific injury, medical condition, or specific topic, only 13 articles focused specifically on the RTP decision-making process, and 6 of 13 were restricted to Step 1 of the 3-step model (Medical Factors). Return-to-play is a fertile field for research and thought leadership beginning with a focus on the Team Physician's appropriate role in RTP decision making, particularly considering the factors identified in Step 3 (Decision Modification). Language: en

Purpose: Over the past decade several authors have focused on the demand for anesthesiologist services. The objective of this article is to determine the clinical work billed by Canadian anesthesiologists at different stages of practice. Methods: Ten years worth of specialist anesthesiologists' billing data from Jan 1, 1993 to Dec 31, 2002 were obtained from British Columbia (BC), Ontario (Ont), and Quebec (Que). The anesthesiologists were stratified into three age categories (

OBJECTIVE To identify the nature and extent of research in sport injury prevention with respect to 3 main categories: (1) training, (2) equipment, and (3) rules and regulations. DATA SOURCES We searched PubMed, CINAHL, Web of Science, Embase, and SPORTDiscus to retrieve all sports injury prevention publications. Articles were categorized according to the translating research into injury prevention practice model. RESULTS We retrieved 11 859 articles published since 1938. Fifty-six percent (n = 6641) of publications were nonresearch (review articles and editorials). Publications documenting incidence (n = 1354) and etiology (n = 2558) were the most common original research articles (33% of total). Articles reporting preventive measures (n = 708) and efficacy (n = 460) were less common (10% of the total), and those investigating implementation (n = 162) and effectiveness (n = 32) were rare (1% of total). Six hundred seventy-seven studies focused on equipment and devices to protect against injury, whereas 551 investigated various forms of physical training related to injury prevention. Surprisingly, publications studying changes in rules and regulations aimed at increasing safety and reducing injuries were rare (

Objectives To explore the relationship between potential psychological risk factors and injury risk in circus artists. Design Historical cohort study. Setting Cirque du Soleil training programme. Participants Forty-seven circus artists training to become Cirque du Soleil artists. Assessment of risk factors Artists completed the validated REST-Q questionnaire (19 domains) during their first 2 weeks of training. Main outcome Injury risk ratio. Results Of the five a priori exposures of interest, injury, emotional exhaustion, self-efficacy and fatigue were associated with an increase in injury risk (risk ratios between 1.8 and 2.8), but Conflicts/Pressure was not (risk ratio=0.8). Of the several specific psychological aspects that are considered risk factors for injury, low self-efficacy had the strongest relationship. Conclusions Most of the strong psychological risk factors for injuries previously identified in athletes also appear to be risk factors in circus artists.

Meniscal tears are common in sport medicine practice. Many articles and textbooks discuss the relative validity of the different components of the physical examination with respect to their sensitivity, specificity, and positive/negative predictive values as if they were diagnostic tests. In this article, we demonstrate why this approach is limited, including the heterogeneous nature of meniscal tear pathology (e.g., posterior vs anterior). Therefore, in this article, we categorize all the published tests in the literature with regards to the mechanism underlying a positive test. We believe our approach provides the clinician with additional tools to diagnose tears. Future research should explore predictive models based on the different components accounting for heterogeneous pathology and different patient contexts.

OBJECTIVE To describe how different health care specialists manage musculoskeletal injury in children and examine factors influencing return to play decisions. DESIGN National survey. SETTING Secure Web site hosting online questionnaire. PARTICIPANTS Medical doctors, physical therapists, and athletic therapists who were members of their respective sport medicine specialty organizations. INDEPENDENT VARIABLES Professional affiliation and the effect of the following factors were examined: pushy parent, cautious parent, protective equipment, previous injury, musculoskeletal maturity, game importance, position played, team versus individual sport, and time since injury. MAIN OUTCOME MEASURES Recommendation of return to activity after common injuries seen in children and adolescents as described in 5 vignettes; consistency of responses across vignettes. RESULTS The survey was completed by 464 respondents (34%). There were several differences between the professional groups in their recommendations to return to activity. Most factors studied did not tend to influence the decision to return to activity, although protective equipment often increased the response to return sooner. The number of participants who would return a child to activity sooner or later for each factor varied greatly across the 5 vignettes, except for pushy parent or cautious parent. CONCLUSIONS Management practices of sport medicine clinicians vary according to profession, child, clinical factors, and sport-related factors. Decisions regarding return to play vary according to 5 specific characteristics of each clinical case. These findings help establish areas of consensus and disagreement in the management of children with injuries and safe return to physical activity.

Background Although increasing participation in physical activities has significant health benefits, there are no guidelines to help professionals decide when it is safe to return to activity after injury. Objective To examine the specific criteria (eg, strength, pain) that expert sport medicine clinicians use for return to activity decisions in children with musculoskeletal injuries. Methods The authors conducted an online cross-sectional survey of certified Canadian sport medicine doctors (MDs) and sport rehabilitation specialists (physiotherapists (PTs) or athletic therapists (ATs)). The authors asked how they would measure each of the following signs in the context of a knee injury: sport-specific skills, pain, swelling, strength, range of motion (ROM) and balance. Clinicians also ranked the importance of each sign with respect to influencing their recommendations for each of five clinical vignettes. Results The overall response rate was 33.6% (464/1380) with similar rates for each profession. For each clinical sign, all three professions preferred the same measure to determine readiness to return to play: standardised testing for sport-specific skills, impact on function for pain, palpation for swelling, manual muscle testing for strength, visual inspection for ROM and standing on one leg with eyes closed for balance. Regarding importance of specific signs for return to activity, all professions had similar responses for one vignette, but MDs differed from PTs and ATs for the remaining four. Finally, pain was ranked as the no 1 or 2 most important sign in all five vignettes by 41.0% of MDs, 18.1% of ATs and 11.3% of PTs, whereas sport-specific skills was chosen by 9.6% MDs, 12.0% ATs and 16.1% PTs. Conclusion Our results provide the foundation for future work leading towards the development of interdisciplinary consensus guidelines.

CONTEXT: Ice hockey has one of the highest sport participation and injury rates in youth in Canada. Body checking is the predominant mechanism of injury in leagues in which it is permitted. OBJECTIVE: To determine if risk of injury and concussion differ for Pee Wee (ages 11-12 years) ice hockey players in a league in which body checking is permitted (Alberta, Canada) vs a league in which body checking is not permitted (Quebec, Canada). DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study conducted in Alberta and Quebec during the 2007-2008 Pee Wee ice hockey season. Participants (N = 2154) were players from teams in the top 60% of divisions of play. MAIN OUTCOME MEASURES: Incidence rate ratios adjusted for cluster based on Poisson regression for game- and practice-related injury and concussion. RESULTS: Seventy-four Pee Wee teams from Alberta (n = 1108 players) and 76 Pee Wee teams from Quebec (n = 1046 players) completed the study. In total, there were 241 injuries (78 concussions) reported in Alberta (85 077 exposure-hours) and 91 injuries (23 concussions) reported in Quebec (82 099 exposure-hours). For game-related injuries, the Alberta vs Quebec incidence rate ratio was 3.26 (95% confidence interval [CI], 2.31-4.60 [n = 209 and n = 70 for Alberta and Quebec, respectively]) for all injuries, 3.88 (95% CI, 1.91-7.89 [n = 73 and n = 20]) for concussion, 3.30 (95% CI, 1.77-6.17 [n = 51 and n = 16]) for severe injury (time loss, >7 days), and 3.61 (95% CI, 1.16-11.23 [n=14 and n=4]) for severe concussion (time loss, >10 days). The estimated absolute risk reduction (injuries per 1000 player-hours) that would be achieved if body checking were not permitted in Alberta was 2.84 (95% CI, 2.18-3.49) for all game-related injuries, 0.72 (95% CI, 0.40-1.04) for severe injuries, 1.08 (95% CI, 0.70-1.46) for concussion, and 0.20 (95% CI, 0.04-0.37) for severe concussion. There was no difference between provinces for practice-related injuries. CONCLUSION: Among 11- to 12-year-old ice hockey players, playing in a league in which body checking is permitted compared with playing in a league in which body checking is not permitted was associated with a 3-fold increased risk of all game-related injuries and the categories of concussion, severe injury, and severe concussion. Language: en

BACKGROUND: The ability to digest lactose divides the world’s population into two phenotypes that may be risk variability markers for several diseases. Prebiotic effects likely favour lactose maldigesters who experience lactose spilling into their colon.OBJECTIVE: To evaluate the effects of fixed-dose lactose solutions on fecal bifidobacteria and lactobacilli in digesters and maldigesters, and to determine whether the concept of a difference in ability to digest lactose is supported.METHODS: A four-week study was performed in 23 lactose mal-digesters and 18 digesters. Following two weeks of dairy food withdrawal, subjects ingested 25 g of lactose twice a day for two weeks. Stool bifidobacteria and lactobacilli counts pre- and postintervention were measured as the primary outcome. For secondary outcomes, total anaerobes, Enterobacteriaceae, beta-galactosidase and N-acetyl-beta-D-glucosaminidase activity in stool, as well as breath hydrogen and symptoms following lactose challenge tests, were measured.RESULTS: Lactose maldigesters had a mean change difference (0.72 log10colony forming units/g stool; P=0.04) in bifidobacteria counts compared with lactose digesters. Lactobacilli counts were increased, but not significantly. Nevertheless, reduced breath hydrogen after lactose ingestion correlated with lactobacilli (r=−0.5; PCONCLUSIONS: Despite failure to achieve full colonic adaptation, the present study provided evidence for a differential impact of lactose on microflora depending on genetic lactase status. A prebiotic effect was evident in lactose maldigesters but not in lactose digesters. This may play a role in modifying the mechanisms of certain disease risks related to dairy food consumption between the two phenotypes.

The analysis of injury data requires different considerations from the analysis of other types of outcomes because an individual can experience the outcome many times. When describing injury patterns using numerator-only data (e.g., proportion of upper-extremity injuries vs. lower-extremity injuries), simple comparisons of proportions are inappropriate because 1) individuals are compared with themselves and 2) multiple testing increases the potential for incorrect inference. Bootstrapping (resampling) techniques can be used to determine confidence intervals and whether the frequencies significantly differ across categories. When describing injury rates, the authors suggest plotting the observed injury rate against the number of exposures to obtain a visual representation of the heterogeneity of risk across individuals. Because the distribution of injury rates is often skewed, some research questions may be best addressed by comparing the weighted median injury rates instead of the weighted mean injury rates (which are given by standard formulae). Again, resampling techniques can be used to obtain a null distribution for injury rates in order to determine whether there are subjects who have unexpectedly high injury rates. More advanced analyses are required to account for multiplicity.

Although the Canadian pharmaceutical industry claims to be spending about $1 billion per year for research and development (R&D), there is little evidence of research performed, as measured by scientific publications and patent applications. One firm was exceptional; it compared favourably with its parent firm in regard to the number of publications and patents in relation to the R&D budget, demonstrating the feasibility of developing a productive and independent research program in Canada. The perception of low productivity is made worse by the inadequacy of the annual report on R&D prepared by the Patented Medicines Prices Review Board (PMPRB). We recommend a number of changes in the PMPRB’s mandate so that its collection of R&D data and subsequent analysis will be more complete. Further financial assistance to the industry should be withheld until accountability is assured and a full assessment of the outcome of its R&D program can be made.

Some authors argue that systematic reviews and meta-analyses of intervention studies should include only randomized controlled trials because the randomized controlled trial is a more valid study design for causal inference compared with the observational study design. However, a review of the principal elements underlying this claim (randomization removes the chance of confounding, and the double-blind process minimizes biases caused by the placebo effect) suggests that both classes of study designs have strengths and weaknesses, and including information from observational studies may improve the inference based on only randomized controlled trials. Furthermore, a review of empirical studies suggests that meta-analyses based on observational studies generally produce estimates of effect similar to those from meta-analyses based on randomized controlled trials. The authors found that the advantages of including both observational studies and randomized studies in a meta-analysis could outweigh the disadvantages in many situations and that observational studies should not be excluded a priori.

We used in situ gastrocnemius muscle of anaesthetized dogs to test the hypothesis that O2 radical production during muscle contraction contributes to fatigue. Muscle tension was measured with a force transducer and blood flow was monitored with an electromagnetic flow probe. Muscle contractions were produced by stimulating the nerve for 15 min at 20 Hz, 12 trains/min, and a duty cycle of 0.25. Three groups of seven animals were given an infusion of 0.2 mL∙min−1 of either saline, low-dose oxygen radical scavengers (250 IU∙mL−1 superoxide dismutase, 640 IU∙mL−1 polyethylene glycol (PEG)-catalase, 0.25 mg∙mL−1 deferoxamine, and 0.1 mg∙mL−1 oxypurinol), or high-dose oxygen radical scavengers (3300 IU∙mL−1 uperoxide dismutase, 6600 IU∙mL−1 PEG-catalase, 2.5 mg∙mL−1 deferoxamine, and 0.1 mg∙mL−1 oxypurinol). Blood flow and vascular resistance of the gastrocnemius muscle during stimulation did not differ among groups. After 15 min of stimulation, the developed tension (represented as a percentage of initial tension developed) was 66 ± 7% in the saline treated group, 70 ± 6% in the low-dose group, and 70 ± 4% in the high-dose group. The change in tension during recovery was not significant in the control or low-dose groups. However, there was partial recovery in the high-dose group. In conclusion, in this preparation, oxygen radical scavengers did not delay the development of decreased muscle tension.Key words: muscle fatigue, oxygen free radicals, resistance, flow.

Background The objective of most biomedical research is to determine an unbiased estimate of effect for an exposure on an outcome, i.e. to make causal inferences about the exposure. Recent developments in epidemiology have shown that traditional methods of identifying confounding and adjusting for confounding may be inadequate. Discussion The traditional methods of adjusting for "potential confounders" may introduce conditional associations and bias rather than minimize it. Although previous published articles have discussed the role of the causal directed acyclic graph approach (DAGs) with respect to confounding, many clinical problems require complicated DAGs and therefore investigators may continue to use traditional practices because they do not have the tools necessary to properly use the DAG approach. The purpose of this manuscript is to demonstrate a simple 6-step approach to the use of DAGs, and also to explain why the method works from a conceptual point of view. Summary Using the simple 6-step DAG approach to confounding and selection bias discussed is likely to reduce the degree of bias for the effect estimate in the chosen statistical model.

Background Very low birthweight infants are at risk for deficits in cognitive and language development, as well as attention and behaviour problems. Maternal sensitive behaviour (i.e. awareness of infant cues and appropriate responsiveness to those cues) in interaction with her very low birthweight infant is associated with better outcomes in these domains; however, maternal anxiety interferes with the mother's ability to interact sensitively with her very low birthweight infant. There is a need for brief, cost-effective and timely interventions that address both maternal psychological distress and interactive behaviour. The Cues and Care trial is a randomized controlled trial of an intervention designed to reduce maternal anxiety and promote sensitive interaction in mothers of very low birthweight infants. Methods and design Mothers of singleton infants born at weights below 1500 g are recruited in the neonatal intensive care units of 2 tertiary care hospitals, and are randomly assigned to the experimental (Cues) intervention or to an attention control (Care) condition. The Cues intervention teaches mothers to attend to their own physiological, cognitive, and emotional cues that signal anxiety and worry, and to use cognitive-behavioural strategies to reduce distress. Mothers are also taught to understand infant cues and to respond sensitively to those cues. Mothers in the Care group receive general information about infant care. Both groups have 6 contacts with a trained intervener; 5 of the 6 sessions take place during the infant's hospitalization, and the sixth contact occurs after discharge, in the participant mother's home. The primary outcome is maternal symptoms of anxiety, assessed via self-report questionnaire immediately post-intervention. Secondary outcomes include maternal sensitive behaviour, maternal symptoms of posttraumatic stress, and infant development at 6 months corrected age. Discussion The Cues and Care trial will provide important information on the efficacy of a brief, skills-based intervention to reduce anxiety and increase sensitivity in mothers of very low birthweight infants. A brief intervention of this nature may be more readily implemented as part of standard neonatal intensive care than broad-based, multi-component interventions. By intervening early, we aim to optimize developmental outcomes in these high risk infants. Trial Registration Current Controlled Trials ISRCTN00918472 The Cues and Care Trial: A randomized controlled trial of an intervention to reduce maternal anxiety and improve developmental outcomes in very low birthweight infants

Background Discrepancies between the conclusions of different meta-analyses (quantitative syntheses of systematic reviews) are often ascribed to methodological differences. The objective of this study was to determine the discordance in interpretations when meta-analysts are presented with identical data. Methods We searched the literature for all randomized clinical trials (RCT) and review articles on the efficacy of intravenous magnesium in the early post-myocardial infarction period. We organized the articles chronologically and grouped them in packages. The first package included the first RCT, and a summary of the review articles published prior to first RCT. The second package contained the second and third RCT, a meta-analysis based on the data, and a summary of all review articles published prior to the third RCT. Similar packages were created for the 5th RCT, 10th RCT, 20th RCT and 23rd RCT (all articles). We presented the packages one at a time to eight different reviewers and asked them to answer three clinical questions after each package based solely on the information provided. The clinical questions included whether 1) they believed magnesium is now proven beneficial, 2) they believed magnesium will eventually be proven to be beneficial, and 3) they would recommend its use at this time. Results There was considerable disagreement among the reviewers for each package, and for each question. The discrepancies increased when the heterogeneity of the data increased. In addition, some reviewers became more sceptical of the effectiveness of magnesium over time, and some reviewers became less sceptical. Conclusion The interpretation of the results of systematic reviews with meta-analyses includes a subjective component that can lead to discordant conclusions that are independent of the methodology used to obtain or analyse the data.

Several retrospective studies, including our previous investigation, have shown a prognostic value of nuclear shape factor in colorectal carcinomas. This prospective study was designed to assess the reliability of nuclear shape factor determined by nuclear morphometry and to confirm its prognostic value.Ninety-eight patients who underwent colorectal carcinoma resection were prospectively enrolled. Measurement of nuclear shape factor was performed by using a computer-based image analysis system. Nuclear shape factor was defined as the degree of circularity of the nucleus (1.0 for a perfect circle and1.0 for any other elliptical shape). The prognostic impact of nuclear shape factor on ten-year survival and the intraobserver and interobserver agreement were assessed.The nuclear shape factor mean values by American Joint Committee on Cancer stage were: 0.73 (0.07) in Stage I, 0.74 (0.06) in Stage II, and 0.75 (0.05) in Stage III carcinomas (P = 0.78, ANOVA). The intraobserver agreement was poor for observer A (r = 0.28) and practically nonexistent for observer B (r = -0.004, Pearson correlation). The intraclass coefficient for interobserver agreement was practically nonexistent. No significant association between nuclear shape factor and ten-year survival was found.Our prospective results, as opposed to our previous retrospective results, suggest that the reliability for nuclear shape factor morphometric analysis is very poor. We failed to confirm a prognostic value for nuclear shape factor in colorectal carcinoma.

Although physical activity reduces mortality and morbidity, injuries associated with activity may increase both short- and long-term musculoskeletal disability. On the basis of basic science and injury epidemiology studies, authors have made conclusions about cause and effect (causal inferences) and have suggested various interventions to decrease the rate of injuries. However, recent advances in epidemiology suggest that the regression/stratification approach to adjustment for confounding does not provide an appropriate foundation for causal inference; therefore, hypotheses based on traditional analyses may be misleading. The purpose of this article is to provide an overview of the basic concepts of injury epidemiology related to causes, risk factors, and confounding, and to conceptually explain the more recent advances that allow for appropriate interpretations of cause and effect.

To determine the proportion of family physicians who diagnose rheumatoid arthritis (RA) correctly and to note how they report they would manage RA patients.Mailed survey (self-administered questionnaire) requesting comments on vignettes.Province of Quebec.Computer-generated random sample of family physicians registered with the Quebec College of Family Physicians.The proportion of family physicians who recognized RA and their reported management strategies.Most respondents recognized the vignette presentation as a case of RA; 133/138 (96.4%) indicated RA as their provisional diagnosis, and all but 1 of the remaining respondents listed RA as a differential diagnosis. Of those who considered RA as a provisional or possible diagnosis, 107 (77.5% of all respondents) suggested referring the patient to a rheumatologist. Among the physicians who suggested referral, none indicated they would initiate disease-modifying antirheumatic drugs (DMARDs).Almost all respondents considered RA as a provisional or differential diagnosis. Although many suggested referring the patient to a rheumatologist, almost a quarter did not. Initiating DMARDs before referring patients to rheumatologists appears to be rare. Since DMARDs given during the early stages of RA are known to decrease damage and dysfunction, ways to increase their use and optimize care pathways for new-onset inflammatory arthritis are urgently needed.

To describe the knowledge and attitudes about confidentiality issues within family medicine teaching units (FMUs) at McGill University.The authors surveyed McGill University FMU staff (physicians, nurses, and support staff) on their knowledge of and attitudes toward confidentiality issues.The response rate was 84%. Only one of nine questions on confidentiality laws was correctly answered by more than 80% of the respondents. Only 55% of the support staff knew that police are not permitted free access to charts, although the majority of those who answered incorrectly held attitudes that were consistent with the law. Only approximately 25% knew that physicians and nurses are not permitted free access to any medical record within the center. There were minimal differences between the professions or between the FMUs.These findings suggest that FMU staff do not fully understand their obligations towards patient confidentiality.

A survey was undertaken at a single Academic Health Sciences Centre to document the opinions of anesthesiologists regarding what variables are important to document on the anesthetic record. A subsequent chart review of anesthetic records was undertaken to determine the extent to which these anesthesiologists record the variables they consider important.A survey form was mailed to all practicing staff anesthesiologists at the four adult McGill University affiliated hospitals. Anesthesiologists were asked to rank 23 preoperative and 33 intraoperative variables on a scale from 1-5: (1 = essential; 2 = important; 3 = useful; 4 = not important; 5 = excessive information). All variables considered by consensusor = 2 (important to essential) were then assessed as to whether they were recorded on 60 charts randomly selected from each of the four teaching hospitals. Only anesthetic records completed by staff anesthesiologists were evaluated.Ninety percent (47/52) of survey forms were completed and returned. Preoperative variables considered most important to document included examination of the patient's airway and allergy status. Intraoperative variables considered most important for documentation were the patient's vital signs. The only variable to have been recorded on all the anesthetic records was the anesthesiologist's name. The allergy status was the most recorded preoperative variable (84% of charts). The recording rates of intraoperative variables ranged from 100% (anesthesiologist's name, start time of anesthesia) to 24% (estimated blood loss).McGill anesthesiologists consider many preoperative and intraoperative variables to be important to document on the anesthetic record. However, subsequent chart review indicated that many of these variables are recorded inconsistently. The transmission of anesthesia-related medical information might be improved if anesthesiologists recorded more consistently information they consider to be important.

Purpose: To compare changes in jump height and running velocity with and without pre-event high-velocity, low-amplitude manipulation (HVLA). Methods: A crossover study design with elite healthy athletes was used. After a 15 min warm-up, the subjects were tested for countermovement jump height (CMJ) and flying 40 m sprint time (SPRINT). A sport chiropractor then evaluated each subject. Subjects were randomised to either HVLA (applied to joints based on examination) or placebo (simulated performance-enhancement stickers). They then rested for 60 min, performed another 15 min warm-up, and were retested. The protocol was repeated 48 h later with the alternative intervention. The mean of two sprints and three jumps were analysed, as well as peak performances. The sample size was based on prior results from the effects of stretching. Results: 19 subjects involved in sprint sports were enrolled; two were too sore to participate on day 2, and one could only participate in the jump (all had HVLA on day 1). Of the 17 participants analysed, seven were female, age range was 19–35, and 17 were national or world-class athletes. The ranges for baseline measures were: SPRINT 4.1–5.5 s; CMJ 47.4–92.7 cm. Overall, the greater than expected variability in this pilot study led to the study being underpowered. Subjects tended to perform better after HVLA for both CMJ and SPRINT (both mean and peak results), but none of the results were statistically significant (p = 0.30–0.61). Conclusion: Although the larger than expected variability in the pilot study means that the observed clinically relevant differences were not statistically significant, the direction and magnitude of the changes associated with HVLA suggest that it may be beneficial. That said, the increased soreness after HVLA suggests that it may be detrimental. HVLA warrants further study.

A survey was undertaken at a single Academic Health Sciences Centre to document the opinions of anesthesiologists regarding what variables are important to document on the anesthetic record. A subsequent chart review of anesthetic records was undertaken to determine the extent to which these anesthesiologists record the variables they consider important.A survey form was mailed to all practicing staff anesthesiologists at the four adult McGill University affiliated hospitals. Anesthesiologists were asked to rank 23 preoperative and 33 intraoperative variables on a scale from 1-5: (1 = essential; 2 = important; 3 = useful; 4 = not important; 5 = excessive information). All variables considered by consensus ≤ 2 (important to essential) were then assessed as to whether they were recorded on 60 charts randomly selected from each of the four teaching hospitals. Only anesthetic records completed by staff anesthesiologists were evaluated.Ninety percent (47/52) of survey forms were completed and returned. Preoperative variables considered most important to document included examination of the patient's airway and allergy status. Intraoperative variables considered most important for documentation were the patient's vital signs. The only variable to have been recorded on all the anesthetic records was the anesthesiologist's name. The allergy status was the most recorded preoperative variable (84% of charts). The recording rates of intraoperative variables ranged from 100% (anesthesiologist's name, start time of anesthesia) to 24% (estimated blood loss).McGill anesthesiologists consider many preoperative and intraoperative variables to be important to document on the anesthetic record. However, subsequent chart review indicated that many of these variables are recorded inconsistently. The transmission of anesthesia-related medical information might be improved if anesthesiologists recorded more consistently information they consider to be important.Une enquête a été menée à un Centre universitaire de sciences de la santé pour connaître les opinions des anesthésiologistes sur les variables jugées importantes à inscrire au dossier anesthésique. Une revue subséquente des dossiers anesthésiques a été réalisée pour vérifier si les anesthésiologistes enregistrent les variables qu'ils considèrent importantes. MéTHODE: Un formulaire d'enquête a été posté à tous les anesthésiologistes en exercice dans les quatre hôpitaux pour adultes affiliés à l'université McGill. On leur a demandé de coter 23 variables préopératoires et 33 peropératoires sur une échelle de 1-5: (1 = essentielle, 2 = importante, 3 = utile, 4 = non importante et 5 = surinformation). Toutes les variables reconnues par la majorité ≤ 2 (importante à essentielle) ont été ensuite vérifiées pour savoir si elles étaient enregistrées dans 60 dossiers choisis au hasard dans chacun des quatre hôpitaux d'enseignement. Seuls les dossiers anesthésiques remplis par des spécialistes en service ont été évalués. RéSULTATS: Des formulaires envoyés 90 % (47/52) ont été remplis et retournés. Les variables préopératoires considérées importantes comprenaient l'examen des voies aériennes du patient et la présence d'allergie. Les variables peropératoires prioritaires ont été les signes vitaux des patients. La seule variable enregistrée dans tous les dossiers a été le nom de l'anesthésiologiste. La présence d'allergie a été la variable préopératoire la plus souvent enregistrée (84 % des dossiers). Les taux d'enregistrement des variables peropératoires allait de 100 % (nom de l'anesthésiologiste, heure du début de l'anesthésie) à 24 % (perte sanguine estimée).Les anesthésiologistes de McGill considèrent que de nombreuses variables préopératoires et peropératoires sont importantes à noter au dossier anesthésique. Une revue subséquente des dossiers a indiqué que beaucoup de ces variables ne sont pas constamment inscrites. La transmission des informations médicales liées à l'anesthésie serait améliorée si les anesthésiologistes notaient plus régulièrement les variables qu'ils jugent les plus importantes.

Lacoste M, Therrien M, Cote JN, Shrier I, Labelle H, Prince F. Assessment of seated postural control in children: comparison of a force platform versus a pressure mapping system. Objective To establish the validity and reliability of a pressure mapping system to measure seated postural control in children. Design A concurrent validity and reliability study. Setting Gait and posture laboratory of a rehabilitation center. Participants Thirteen able-bodied children volunteers. Intervention Measurements were taken on a seating simulator in quiet sitting and while reaching. The localization of the center of pressure (COP) in the anteroposterior and mediolateral directions was measured simultaneously by means of a pressure mapping system and a force platform. Main Outcome Measures Concurrent validity was first assessed by Pearson and Spearman correlation coefficients and then by Student paired t tests and Wilcoxon signed-rank test ( P Results The COP signals were significantly correlated between both instruments for the RMS and range in both tasks and directions (mean r ≥.87) and for the time series while reaching ( r ≥.99), as well as during quiet sitting ( r ≥65). Both instruments showed generally fair to good reliability in quiet sitting and excellent reliability when reaching. Conclusions The pressure mapping system can detect the COP displacement as effectively as the force platform. In a clinical context, it could help in the evaluation of seated stability and also help in evaluating the efficacy of seating components for wheelchair users.

In recent years, several authors have suggested there is a need for more very large or "mega-trials" (defined in this manuscript as a trial powered to address subgroup differences/interactions/secondary analyses) to answer important clinical questions. Because mega-trials are expensive and funding for clinical research is limited, increasing the number of mega-trials limits funding for other research. The advantages of this approach compared with funding more focused RCTs needs to be debated. Because there is no method to determine gold standard for which method gives the correct answer, we provide theoretical arguments that demonstrate that the two approaches are similar with respect to sample size requirements and the mega-trial approach provides a small advantage with respect to minimizing confounding by chance. However, the inherent heterogeneity in a series of smaller trials may represent a significant advantage over a single mega-trial.

Many articles provide only odds ratios (OR) and non relative risks (RR) as the effect estimate. For a variety of important reasons, multiple logistic regression used to adjust for confounders routinely provides only the adjusted OR (ORadj). However, from the clinician's perspective, the ORadj is only easily interpretable when it approximates the adjusted RR (RRadj). In general, the relationship between the OR and RR (adjusted or nonadjusted) is dependent on prevalence of disease in the control group (Po) and has always been presented as nonlinear. Therefore, it is difficult for the clinician to convert the OR to RR when reading the published data. A formula was proposed by Zhang and Yu, but the relationship remains nonlinear.To develop a simple method to convert OR to RR without the use of computer.Algebraic manipulation.Through algebraic manipulation, we show that although the OR and RR relationship is nonlinear over the range Po, the ratio OR/RR has a linear relationship with Po with a slope of "OR-1": OR/RR=(OR-1)xPo+1. This makes the prediction of RR on the basis of OR more transparent. It is clear that if Po is small, the RR approximates the OR, but only if the OR is also small. Previous problems with confidence intervals noted with the Zhang and Yu formula remain (ie, they are too narrow under some conditions) and the result should be interpreted with this limitation. Relationships between ORadj and risk difference or number needed to treat remain curvilinear, but some overall approximations can be made.A simple relationship exists that allows readers to easily convert ORadj to RRadj. Limitations of the approach remain but seem to be less restrictive than the limitations of not converting ORadj to RRadj.

Summary Osteoarthritis (OA) is the most frequent joint disorder in seniors. Systematic reviews suggest that conservative treatment is effective and preferred in mild-moderate cases. The objective of this study was to examine the proportion of patients receiving physiotherapy, exercise or walking aids, and to explore factors associated with their prescription. We conducted a retrospective survey of patients about to undergo total hip arthroplasty for hip osteoarthritis. Patients were asked about past prescriptions for cane use, physiotherapy and exercise. Of 161 patients (36.6% male, mean age 68.7 ± 10.1 years), 76% were prescribed a cane (adherence = 86.2%). The main reason for not using a cane was vanity. Of the 28.0% patients prescribed physiotherapy, 73.3% received exercises compared to only 2.6% of non-physiotherapy patients. Patients who were older or worked in manual labour were more likely to be prescribed a cane and less likely to be prescribed physiotherapy or exercises. Men were less likely than women to be prescribed all three, but only cane use was statistically significant across genders. In conclusion, physiotherapy and exercise are not commonly prescribed in patients with hip OA.

Objective: To evaluate risk factors for venous thromboembolism (VTE) despite thromboprophylaxis in major orthopedic surgery patients at a tertiary care hospital. Methods: Charts from consecutive patients who underwent total hip replacement (THR), total knee replacement (TKR), or hip fracture surgery (HFS) [hip pinning or hemiarthroplasty] from August 1, 1999, to April 30, 2000, at a large Canadian teaching hospital were abstracted using standardized case report forms. Data were collected on patient characteristics, surgical characteristics, and thromboprophylaxis regimen. Results of tests performed for suspected VTE were documented. Associations between characteristics of interest and objectively confirmed VTE were examined in multivariate analysis. Results: Over the study period, 310 patients underwent major orthopedic surgery and received standard thromboprophylaxis with either dalteparin or enoxaparin (mean duration of prophylaxis, 7 days). Of these, 34% underwent THR, 30% underwent TKR, and 36% underwent HFS. Of 83 suspected cases of VTE, 44 cases (7 proximal and 37 distal deep venous thrombosis [DVT]); 14% of study population) were confirmed with objective testing. Multivariate analyses revealed that knee surgery (odds ratio [OR], 4.8; 95% confidence interval [CI], 2.3 to 10.1) and type of low molecular weight heparin (LMWH) [enoxaparin (more protective): OR, 0.39; 95% CI, 0.20 to 0.80] independently predicted VTE. No patient characteristics (including previous VTE, malignancy, hormonal therapy, postoperative complications) were associated with VTE. Conclusion: Despite standard thromboprophylaxis, symptomatic breakthrough VTE, primarily distal DVT, developed in 14% of patients undergoing major orthopedic surgery. Factors that independently predicted VTE in our population were TKR surgery and type of LMWH. TKR patients may warrant more aggressive postoperative physiotherapy and ambulation and adjunctive prophylactic measures such as pneumatic compression. Due to the heterogeneity of different LMWH compounds, direct comparison of the effectiveness of enoxaparin with dalteparin for orthopedic prophylaxis in prospective, randomized trials seems warranted.

Background:Toourknowledge,theburdenofdeepvenous thrombosis from the patient’s perspective has not been quantified. We evaluated health-related quality of life (QOL) after deep vein thrombosis and compared results with general population norms. Methods: This was a multicenter prospective cohort study of 359 consecutive eligible patients with deep vein thrombosisrecruitedat7Canadianhospitalcenters.Quality of life was assessed at baseline and at 1 and 4 months afterdiagnosisusinggeneric(36-ItemShort-FormHealth Survey) and disease-specific (Venous Insufficiency Epidemiological and Economic Study [VEINES]–QOL and VEINES symptom [VEINES-Sym] questionnaires) measures. Changes in QOL scores during the 4-month period were calculated, and determinants of lack of improvement in QOL were evaluated. Results: During the 4 months, mean 36-Item ShortFormHealthSurveyphysicalandmentalcomponentsummary scores improved by 5.1 and 4.6 points, respectively, and VEINES-QOL and VEINES-Sym scores improved by 3.1 and 2.2 points, respectively (P.001 fortimetrendforallmeasures).However,aboutonethird ofpatientshadworseningofQOLduringfollow-up.Multivariate analyses showed that worsening of the postthrombotic syndrome score was an independent predictor of worsening of 36-Item Short-Form Health Survey physical component summary (P=.04), VEINES-QOL (P.001), and VEINES-Sym (P.001) scores. The 36ItemShort-FormHealthSurveyphysicalcomponentsummary scores were lower than population norms at all points assessed. Conclusions: On average, QOL improves during the 4 months following deep vein thrombosis. However, in about one third of patients, QOL deteriorates, and at 4 months, average QOL remains poorer than population norms.Worseningofthepostthromboticsyndromescore is associated with worsening of QOL. Arch Intern Med. 2005;165:1173-1178